Acoustical wall covering



Patented Mar. 2, 1943 ACOUSTICAL WALL COVERING Kenneth S. Rankin, Toronto, Ontario; Canada,

assignor to Acousticwall Limited, Toronto, On-

tario, Canada No Drawing. Application July 7, 1939, Serial No. zsam Claims. (Cl. 106-122) This invention relates to material for covering the surface of walls of buildings which has the characteristic of deadening or absorbing sound and the principal objects of this invention are to produce. a composite material with an extremely sound-absorbing co-efiicient and which is non-inflammable or fire-resistant and is extremely light in weight, and which when finished presents a smooth even surface and will not shed dust through vibration or from contact.

The principal features of the invention consist in the admixture of calcined diatomaceous earth with a noninflammable fibre suchas finely spun or thread-like glass, 9. suitable commercial example of which is known under the trade name Fibreglass, and an admixture therewith of asbestos fibre and a suitable adhesive binder to tie these materials together in an open or porous structure.

It is well known to those skilled in the art of preparing and applying surface coatings to walls that either the suction of the base upon which the coating is placed is depended upon to hold the surface coating in position when drying, or to the feature of mechanical keys or interlocks when the surface is applied over lath material.

With suction coatings the suction draws the water from the mix and extensively reduces the interstices or spaces between the fibre which would be left if the material were dried entirely by the slower process of evaporation.

When the material is made to depend upon its mechanical adhesion by keying to the lath or surface structure the water content is reduced to a minimum in order to make the mix strong enough and tacky enough to hold itself in position.

y The present invention has been devised with the intention of having mixed with the solid ingredients the largest possible quantity of water which is to be removed by evaporation in such a manner that the fibrous nature of the solids will not collapse and the interstices between such fibres created by the presence of the water will be sustained in the drying operation.

In the preferred composition which I have found to produce extraordinary results I com- Titanium oxide without very much alteration in the ultimate result, that is to say, the calcined diatomaceous earth may be diatomite, infusorial earth, kieselguhr, or tripoii, and while the finely spun glass is the most desirable, rock wool or slag wool may be substituted therefor, but will not sustain the same water content or achieve as good a coverage or structural strength and there will bean appreciable lessening of the acoustical properties.

The titanium oxide is incorporated in the mixture for the purpose of giving to the substance a clean, white surface but this material might be substituted by lithophone or other white pigment, but titanium oxide is desired as being permanent and very light in weight.

A composition such as described maybe spread easily over a wall or ceiling surface and will have a remarkable covering capacity due in large measure to the exceptionally high water content which high content has a direct bearing on the high acoustical values obtained since its ultimate evaporation leaves voids on evaporation which would otherwise not be possible where a low water content must be employed as in present practice.

It is well known and understood by those skilled in the use of these materials that diatomaceous earth is highly hygroscopic and absorbs considerable water. Therefore in the evaporation of the water the porous particles of the diatomaceous earth have a great tendency to shrink but their intimate association with the finely spun glass and asbestos hold such drying particles from shrinking and 'knotting in spots and creating an unequal distribution. Therefore the ultimate wall covering will be characterized by the pronounced structural strength of the finely spun glass and asbestos fibre and the presence of a high percentage of interstices throughout the same in ratio to volume due in large part to the function of the calcined diatomaceous earth in absorbing a. high water content which is subsequently evaporated cast in the desired shape.

' composite material up to one half leaving a felted fibrous mass and due as well to the absence of any high solid content in the binder.

rIt has found in practice that a material such as above described can be readily applied towallsurfacesincoatings uptoonehalfan inch in one application. The extraordinarily high percentage by bulk of the diatomaceous earth not only provides an apparently closed surface but this surface is velvet-like in appearance and is particularly suitable for ceilings or upper parts of walls and its bright lustrous light refracting qualities are quite important due to the extensive mineral content of the finely spun glass and asbestos and it does not possess the glare effect of glossy surfaces.

A very desirable feature of this composition is its extreme lightness of weight which when used on ceilings reduces the ceiling load to a minimum.

A. coating of such material as herein described applied in the thickness of one half inch to a wall has an extremely high sound-absorption co emcient. The extremely high mineral content renders the surface, fireproof and it will withstand a temperature up to 1800 F. under direct flame without melting.

With the saponified sizing defined the material is waterproof and it is also vermin-proof.

It will be appreciated that a covering of this nature may have colouring matter added in order to produce any colour or shade which may be desired and the amount of such colouring ma- What I claim as my invention is:

1. An acoustic covering forwalls and ceilings formed essentially of finely spun glass bonded together in an intersticial felted mass and characterized mainly by its sound-absorbing properties. a

2. An acoustic wall covering formed essentially of finely spun glass in combination with calcined diatomite, mineral fibre and a binder of the saponified class, said covering 'being characterized mainly by its sound-absorbing properties, tness and structural strength.

3. An acoustic covering for walls or the like of the type containing diatomaceous earth. fibrous material and a bonding medium, characterized in that the diatomaceous earth is calcined and the fibrous material mainly comprises finely spun glass, the bonding medium holding the other elements in substantially uniform dispersion. the covering being further characterized mainly by its sound-absorbing quality and lightness due to the manifold interstices therein.

4. A composition of the type set forth in claim 3 in which the calcined diatomaceous earth and the finely spun glass are present in substantially equal proportions, the remaining portion of the fibrous material comprising essentially asbestos fibre representing substantially one fifth the combined quantity of the calcined diatomaceous earth and the finely spun glass,

in combination with a saponified binder as the a bonding medium and-adapted when mixed with terial will be so small that it will not affect I may be applied to the smooth face of the wall to ensure its adhesionand a surface coating of the an inch in thicmess may be applied.

approximately one and one-half times the weight of the combined ingredients of water to form'a composition capable of being applied to walls, ceilings and the like in thicknesses up to onehalf inch and further characterized essentially by its pronounced sound-absorbing properties.

lightness, structural strength and soft ,velvetlike appearance on dispersion of the high water content. I

5. A composition for acoustically treating wall surfaces or the like formed essentially of the following ingredientsin substantially the following proportions, calcined diatomite five pounds, finely spunjglass six pounds, asbestos 1 fibre two pounds, a saponified binder six pounds, and water thirty pounds.

KENNEI'H s. 

